The game had been under development by a relatively small team for at least six years, and is the sequel to the studio's popular 2002 Half-Life mod, which was available for free. This commercial follow-up is a standalone digital-only release built on a proprietary engine.

Unknown Worlds has posted an infographic demonstrating the success it's seen on Steam so far, noting that it's so far sold more than 144,000 copies (the company offers a four-pack edition, allowing consumers to buy multiple copies for friends at a discount).